Strategy Academy

One idea at a time, then practise it.

Start at the top — even old hands find something new in the basics.

1How Sudoku WorksBasics · 2 min · One of each digit, three ways.Naked SingleBasics · 3 min · One cell, one survivor.Hidden SingleBasics · 3 min · A digit with only one home.Naked PairIntermediate · 4 min · Two cells reserve two digits.Pointing PairIntermediate · 4 min · A box points down a line.X-WingAdvanced · 5 min · Four corners, one elimination.